Regarding the technologies for making a repair of flaws produced on the surface of hot-rolled steel products such as sheet bars during the hot rolling process and for removing projections inevitably produced in the joint portion in the continuous hot rolling process in which rolling is carried out by butt joining the tail edge of preceding steel product to the leading edge of following steel product, many proposals have already been made in Unexamined Japanese Patent Publication No. 57-137008, Unexamined Japanese Patent Publication No. 63-160707, Unexamined Japanese Patent Publication No. 5-23706, Unexamined Japanese Patent Publication No. 5-104261, Unexamined Japanese Patent Publication No. 57-91856, Unexamined Japanese Patent Publication No. 53-112593, and so forth.
However, these technologies have disadvantages that there arises a trouble of breaking of a hot-rolled steel product (hereinafter referred simply as to a steel product) in surface- cutting the steel product, and that the improvement in cutting efficiency cannot be achieved because the life of cutting edge is short and quick action cannot be taken when local wear of cutting edge occurs. Also, there remain problems in that it is difficult to adjust a predetermined allowance in cutting a steel product, that the equipment is damaged by the contact of cutting edges which cut a steel product from upside and downside, that chips produced by cutting cannot be disposed well, and that fluttering of steel product occurs during the cutting process.
An object of the present invention is to provide a method and apparatus which can solve all above-described conventional problems occurring in surface cutting of steel products.